Chttsetts



Jan, 17

D. FAY ET AL SOUND RADIATING DEVICE Filed Nov. 16, 1925 Patented .lan,17, 1928',

UNITED srA'rns PA ENT OFFICE.

RICHARD ID. FAY. OF CAMFRIDGE, A ND ROBERT E. BREWER, OF BOSTON, MASSA-I CHUSETTS.

sounn-nnnmrine D VICE.

Original application filed Our invention relates to sound-radiatingdevices particularly;adapted for use with radlophone receiving systems,although capable of more general application and not 0 limited to 'suchuse, and its object; is to produce a device of this character in whichthe wave fronts of the radiatedsoundwaves areinitiallycurvilinearoutwardly so that there sitely-disposcd substantially-rigid arms a'd--j.t ls tableby the screw support two oppoeomprises anoutwardlylaringconical tymwill bra-substantially no directional etfeet.1U \Vitli this object '11 view our invention panum havingits heightsorelated to the length of its generatri'x that the wave fronts of thesound waves radiated theretrbrn will be initially curvilinear outwardly.

This application-isa division of our application Serial No.-23,917,filed April 17,1925. In the drawings which accompany and form a partof'thisapplication,

Figure 1 is a longitudinal central section of a conical tympanumconstructed in accordance with ourinvention-; r

Fig. 2 is a longitudinal central section of a conical tympanumhereinafter referred to in explaining the principle of our invention;Fig.3 is a. vertical transverse section of an eleet-rically-operated'sound-radiating device provided with the conical tympanum shown in Fig.-1.

In the cone 10 shown in section in Fig; 2, the height is such that thesound waves radiated therefrom will reach the plane of the base at thesame time that such waves. traveling through the material of the conefrom the apex ll reach the outer periphery 12, so that the wave front isinitially plane, the dotted lines 13,1 3 indicating the SHCCH- sivcpositions .the wave fronts of the radiated waves. The dotted lines 1-1,H

indicate approximately the wave fronts of the waves radiated from theinner surface of the cone, and it will be-obvious that there will be agreater radiation of energy from November "16', 1925. Seria 1 1 i'o.69,368,:

A ril 17, 1925, Serial No. 23,917. Divided win this appiication m conebase and the "wave front is initially curvilinear outwardly as indicatedby the dotted linc'18.

The sound-radiating member shown in Fig. 1 may be employed withadvantage in an eleclromagnetiea[Le actuated 'smInd-radiating devicesuch as shown in Fig. 2: in which zrpermancnt magnet,- I!) having twoUlllitif ,sitel y-disposed and substantially parallel, flexiblepermeable armaturc-support-i11g members 2-1, in such as relatively stillflexible discs, each clamped between apair of permeable rings 2-2, 22,arranged on the opposite faces of each (llSC near the periphery thereof,by screw or bolts -(not shown) and also by the bolt 24 and nut 2:1- Thesaid .discs are secured to the permanent magnet portion of theircirci'nnference farthest away from their points-of attachment'to thepermanent magnet. Two, oppositely-directed tubular arma tures 26, 26 aresupported on the discs 21, '21 A manner are: the oppositely-disposedsoundradlating members 15, 15 which may be of parchment, fibre, or.anyother suitable ma terial, said memberslming conical and hav-.

ing their peripheral port-ions slightly bent back. as shown at: 27. Eachconical tympanuni' or souml-rzuliating member is sup ported solely atits apex on-its actuating armature by means 'of a sleeve '2S'whiehpasses through the apex and isthrcadcd to the outwardly-projecting endof the armature, said sleeve being formed integral with a conicalportion; 29 to which the tympa num may be attached by gluing orotherwise.

A magnetizing coil 30 is arranged in thev space between the discs and isconcentric with the armatures, said coil being wound on an insulatingspool 31 supported in the present instance in the rabbeted innerpcripheries of the adjacent rings 22.

. apparatus illustrated in Fig. 3 which is shown merely for completenessof'disclosure.

Having thus described an illustrative embodiment of our inventionwithout however limiting the same thereto, what ,we claim and desire tosecure by Letters Patent is .1. In a. sound-radiating device, an outwardly flaring conical tympanum having its height so related to thelength of its generatrix that the wave froiits of the sound curvilinearoutwardly;

2. In a sound-radiating device, a conical tympanum having its height sorelated to its base isless than the time required for a 7 sound wave totravel through the material of saidtympanum from its apex to theperiphery of its-base.

--In testimony whereof, wc-have hereunto subscribed our names this 14thday of- November, 1925. V Y

RICHARD D. FAY. ROBERT E. BREWER.

